As described earlier (Serpell, this volume), the advent of scientific medicine toward the end of the nineteenth century had the effect of displacing companion animals from therapeutic settings until the 1960s when the concept was revived in the writings of Boris M. Levinson. In his book, Pet-Oriented Child Psychotherapy, Levinson described the benefits that his dog brought to his counseling sessions with children and youth, and provided numerous examples of ways in which animals could enhance therapy (Levinson, 1969). Based largely on case studies and anecdotes, Levinson intended for this material to inform and encourage future research into the various beneficial effects that he observed. While this has occurred to some degree, more often Levinson’s writings have been used to justify the implementation of animal-assisted interventions (AAIs) in the absence of valid efficacy studies.
Despite their long history, and the unequivocally positive media attention they typically receive, animal-assisted interventions are currently best described as a category of promising complementary practices that are still struggling to demonstrate their efficacy and validity. Some attempts have been made to standardize terminology and procedures, and various certificate programs are now being offered in association with colleges and universities. However, if the field is to move beyond its fringe status, it must begin to follow the path taken by other alternative and complementary therapies (e.g. psychology, acupuncture, chiropractic, etc.) that have established their credibility by means of carefully controlled clinical trials and valid efficacy studies. With that objective in mind, the goals of this chapter are to clarify the distinction between therapy and other assistive or recreational uses of animals, and then to explore some of the theories that underlie the incorporation of animals into therapeutic contexts.
3.2 Defining animal-assisted interventions
In their critical review of the literature on animal-assisted interventions, Beck and Katcher (1984) aptly state that “a clear distinction should be made between emotional response to animals, that is, their recreational use, and therapy. It should not be concluded that any event that is enjoyed by the patients is a kind of therapy.” Although this statement was made more than 20 years ago, the term animal-assisted therapy continues to be applied to an array of programs that would not qualify as therapy in any scientific/medical sense of the word. The Oxford English Dictionary (1997) defines therapy as “the medical treatment of disease; curative medical or psychiatric treatment.” In contrast, recreation is defined as a “pleasant occupation, pastime or amusement; a pleasurable exercise or employment.” Despite the obvious distinction, there is a tendency in certain quasi-medical fields to weaken or confuse the meaning of the word therapy by linking it to experiences that may provide transient relief or pleasure, but whose practitioners cannot ethically or credibly claim to diagnose or change the course of human disease (e.g. aromatherapy, massage therapy, crystal/gemstone therapy, etc.). Regrettably, this is also the case with many programs that are promoted as animal-assisted therapy. Just as we would not refer to a clown’s visit to a pediatric hospital as clown-assisted therapy, the urge to call animal recreation and visitation programs therapy should be resisted.
In her review of the literature, LaJoie (2003) reports finding 20 different definitions of animal-assisted therapy, and 12 different terms for the same phenomenon (e.g. pet therapy, pet psychotherapy, pet-facilitated therapy, pet-facilitated psychotherapy, four-footed therapy, animal-assisted therapy, animal-facilitated counseling, pet-mediated therapy, pet-oriented psychotherapy, companion/animal therapy, and co-therapy with an animal). This multiplicity of terms and definitions creates confusion both within the field and without. In an attempt to promote the standardization of terminology, the Delta Society (n.d.), one of the largest organizations responsible for the certification of therapy animals in the USA, has published the following widely cited definitions of Animal-Assisted Therapy and Animal-Assisted Activity:
Animal-Assisted Therapy (AAT): AAT is a goal-directed intervention in which an animal that meets specific criteria is an integral part of the treatment process. AAT is directed and/or delivered by a health/human service professional with specialized expertise, and within the scope of practice of his/her profession. Key features include: specified goals and objectives for each individual; and measured progress.
Animal-Assisted Activity (AAA): AAA provides opportunities for motivational, educational, recreational, and/or therapeutic benefits to enhance quality of life. AAAs are delivered in a variety of environments by specially trained professionals, paraprofessionals, and/or volunteers, in association with animals that meet specific criteria. Key features include: absence of specific treatment goals; volunteers and treatment providers are not required to take detailed notes; visit content is spontaneous.
Although the Delta Society lists horses as being animals eligible for certification through their PetPartners® program, interventions involving the use of horses typically fall under the jurisdiction of a separate group of agencies. Prominent among these is the North American Riding for the Handicapped Association (NARHA), its subsection the Equine Facilitated Mental Health Association (EFMHA), and its affiliate-partner the American Hippotherapy Association (AHA), which provide separate definitions for the terms equine-facilitated psychotherapy (EFP) and Hippotherapy:
EFP is an experiential psychotherapy that includes equine(s). It may include, but is not limited to, a number of mutually respectful equine activities such as handling, grooming, longeing (or lunging), riding, driving, and vaulting. EFP is facilitated by a licensed, credentialed mental health professional working with an appropriately credentialed equine professional. EFP may be facilitated by a mental health professional that is dually credentialed as an equine professional (EFMHA, 2003). EFP denotes an ongoing therapeutic relationship with clearly established treatment goals and objectives developed by the therapist in conjunction with the client. The therapist must be an appropriately credentialed mental health professional to legally practice psychotherapy and EFP.
Hippotherapy is done by an Occupational, Physical and Speech Therapist (OT, PT, ST) who has been specially trained to use the movement of the horse to facilitate improvements in their client/patient. It does not teach the client how to ride the horse. Therapists use traditional techniques such as NDT (neurodevelopmental treatment) and SI (sensory integration) along with the movement of the horse as part of their treatment strategy. Goals include: improving balance, coordination, posture, fine motor control, improving articulation, and increasing cognitive skills.
While we include specific definitions of EFP and hippotherapy for the sake of comparison and completeness, the Delta Society definition of AAT is general enough to include these sorts of interventions. What should be emphasized is that these definitions of animal-assisted therapy, equine-facilitated psychotherapy, and hippotherapy all share the following attributes:
The intervention involves the use of an animal or animals.
The intervention must be delivered by, or under the oversight of, a health/human service professional who is practicing within the scope of his/her professional expertise.
It should be noted that the Delta Society definitions include statements about the need for participating animals to “meet specific criteria,” while those utilized by the EFMHA and AHA do not. Ensuring the suitability of an animal for any type of work is of paramount importance for both the animals and the humans involved, and many facilities do require a formal behavioral evaluation prior to allowing animals to interact with clients or patients. However, the criteria by which animals are determined to be suitable for this work are highly variable and often subjective, and what particular interventions require from animals may be diverse and changeable (e.g. some practitioners see a benefit to using skittish or behaviorally challenging animals with particular clients). It is also worth mentioning that formalized behavioral screenings and certifications are not available for all species being used as therapeutic adjuncts, so while these assurances are desirable when available, their absence does not necessarily disqualify a program from being considered therapy. Questions regarding an animal’s suitability for therapy work arise primarily from risk management considerations (e.g. patient safety; liability issues) and concerns about animal welfare. However, these considerations are extraneous to a general definition of therapy. Certainly, such issues should be given top priority when developing and implementing AAIs, but they do not help us to define therapy since an intervention can still achieve therapeutic goals without formal criteria being met by the participating animal(s) (see, e.g. Wells et al.’s (1997) article on the use of feral cats in psychotherapy).
While it would be preferable for this chapter to only include information from studies and programs that adhere strictly to the definition of AAT outlined above—specifically, those that are facilitated by health/human service professionals within the scope of their professional expertise and that have clear treatment goals—too few studies and programs fulfill all the necessary criteria. Therefore, for the purposes of this chapter, animal-assisted therapy, animal-assisted activities, and various equine-facilitated programs are grouped together under the more general term animal-assisted interventions (AAIs)—defined here as “any intervention that intentionally includes or incorporates animals as part of a therapeutic or ameliorative process or milieu.” The Oxford English Dictionary (1997) defines intervention as “the action of intervening, ‘stepping in’, or interfering in any affair, so as to affect its course or issue.” This definition provides the flexibility needed to discuss programs that can fit within a medical model and those of a more quasi-medical nature, but which still seek to “affect the course” of people’s lives in a positive direction.
Guide, assistance, and service animals are purposefully excluded from the above definition of AAIs. The Americans with Disabilities Act of 1990 (ADA) defines a service animal as “any guide dog, signal dog, or other animal individually trained to provide assistance to an individual with a disability” (United States Department of Justice (USDOJ), 1996). The role of the service animal, as defined by the ADA, is to perform some of the functions and tasks that the individual cannot perform as a result of their disability (USDOJ, 1996). While the use of a service animal may provide some psychological benefits to its handler (e.g. decreased feelings of loneliness and isolation, or increased socialization), and not withstanding the nascent use of Psychiatric Service Dogs (Psychiatric Service Dog Society, 2003), service animals are typically viewed as tools rather than treatments, and thus do not constitute an animal-assisted intervention as we define the term.1, 2
3.3 Theoretical frameworks
The field of animal-assisted interventions currently lacks a unified, widely accepted, or empirically supported theoretical framework for explaining how and why relationships between humans and animals are potentially therapeutic. A considerable variety of possible mechanisms of action have been proposed or alluded to in the literature, most of which focus on the supposedly unique intrinsic attributes of animals that appear to contribute to therapy. Others emphasize the value of animals as living instruments that can be used to affect positive changes in patients’ self-concept and behavior through the acquisition of various skills, and the acceptance of personal agency and responsibility. This section presents an overview of the theories most commonly found in the literature and, in some cases, those that seem to offer the best frameworks for future study.3
3.3.1 Intrinsic attributes of animals as contributors to therapy
The notion that animals possess certain inherent qualities that may facilitate therapy is widespread in the AAI literature. According to this view, the mere presence of the animal, its spontaneous behaviors, and its availability for interaction may provide opportunities and confer benefits that would be impossible, or much harder, to obtain in its absence.
Reduction of anxiety and arousal
The idea that the presence of, or interactions with, animals can produce calming effects in humans is commonly cited in the AAI literature. One popular explanation for this phenomenon is derived from E. O. Wilson’s (1984) so-called biophilia hypothesis. This theory asserts that humans possess a genetically based propensity to attend to, and be attracted by, other living organisms (Kahn, 1997) or, as Wilson put it, an “innate tendency to focus on life and lifelike processes” (as cited in Gullone, 2000). The foundation of biophilia is that, from an evolutionary standpoint, humans increased their chances of survival through their attention to, and knowledge of, environmental cues. Clinically speaking, it is hard to imagine a better pairing of attributes—a tool that can simultaneously engage and relax the patient. To quote Melson (2001):
[watching] animals at peace may create a coupling of decreased arousal with sustained attention and alertness, opening the troubled child to new possibilities of learning and growth. The child can then experience unconditional love and models of good nurturing, practice caring sensitively for another, and assume mastery tempered with respect.
Although there are abundant references in the literature that suggest the presence of animals can sometimes exert calming or de-arousing effects on people (Bardill and Hutchinson, 1997; Brickel, 1982; Friedmann et al., 1983; Mallon, 1994a,b; Mason and Hagan, 1999; Reichert, 1998; Reimer, 1999), there are no convincing data demonstrating that these effects are due to any innate attraction to animals. Additionally, Serpell (1986) points out that “it has been known since the 1950s that any stimulus which is attractive or which concentrates the attention has a calming effect on the body,” suggesting that animals may be just one means to this end. Moreover, even proponents of biophilia acknowledge that individual experience and culture play important roles in determining people’s responses to animals (Kahn, 1997; Serpell, 2004).
Brickel (1985) offers learning theory as another explanation for the potential anti-anxiolytic benefits of animals in therapeutic contexts. According to learning theory, an activity that is pleasurable will be self-reinforcing, and will be more likely to occur in the future. Unpleasant or anxiety-provoking activities—e.g. enduring painful or embarrassing visits to a therapist—may result in avoidance or withdrawal behavior. Just as enjoyable activities are self-reinforcing, avoidance of pain and discomfort provides a negative reinforcement by assuring minimal exposure to the painful stimulus. Brickel (1982) suggests that animals introduced in a therapeutic context may serve as a buffer and divert attention from an anxiety-generating stimulus that the patient faces. This interference allows for self-monitored control over exposure to the stimulus instead of withdrawal and avoidance (e.g. a child may choose to reveal sexual abuse first to the therapy animal, rather than revealing it directly to the therapist). If the theory holds, repeated exposure through the animal’s diverting properties, together with non-aversive consequences, should result in the reduction or extinction of anxiety. Brickel does not offer an explanation for why animals, in particular, are apparently so diverting, and it is presumably necessary to resort to other theories to account for this.
While evolutionary and learning theories have not adequately explained why some humans report feeling calmer when an animal is present, numerous researchers have attempted to examine and measure various human physiologic responses to interaction with animals. Studies that have focused on the anti-anxiolytic effects of an animal presence have typically measured heart rate and blood pressure as indicators of arousal (DeMello, 1999; Friedmann et al., 1980, 1983; Katcher et al., 1983), although a subset of studies has collected information on additional variables such as skin temperature, behavioral manifestations of stress, state/trait anxiety, and levels of cholesterol, triglycerides, and phenylethylamine in the plasma (Anderson et al., 1992; Freidmann et al., 2000; Hansen et al., 1999; Nagengast et al., 1997; Odendaal and Lehman, 2000; Wilson, 1991). As with much of the literature on AAIs, findings in this area are conflicting and, regrettably, fundamental methodological differences between the studies make it impossible to draw any firm conclusions about the impact that animals may have on human arousal, since both positive and negative effects have been reported.
Based on all of the available research, the most credible conclusion that one can draw at this stage is that the presence of certain animals can produce calming effects for some people in some contexts, but Wilson’s (1991) finding that interacting with an animal was more stressful than reading quietly does highlight the need for studies that compare animal-assisted interventions with activities with similar aims but that do not incorporate animals. In other words, a finding that the presence of an animal decreases arousal does not rule out the possibility that other interventions or activities that do not include animals might be as, or more, effective.
The observation that animals can serve as catalysts or mediators of human social interactions, and may expedite the rapport-building process between patient and therapist, is often noted in the AAI literature. AAI practitioners and theorists have suggested that animals stimulate conversation by their presence and unscripted behavior, and by providing a neutral, external subject on which to focus (Fine, 2000; Levinson, 1969). Studies that have attempted to look at the social-facilitation effects of animals have produced similarly positive results across a range of populations (e.g. children with physical disabilities; the elderly; college students; typical dog owners; and adult and adolescent psychiatric inpatients). And, drawing from psychoanalytic theory, there are ample references in the AAI literature to patients being able to reveal or discuss difficult thoughts, feelings, motivations, conflicts, or events by projecting them onto a real or fictional animal (Mason and Hagan, 1999; Reichert, 1998; Reimer, 1999; Serpell, 2000; Wells et al., 1997). Reichert (1998) provides this example from her clinical experience with a sexually abused child:
I told one child that Buster [a dog] had a nightmare. I then asked the child, “What do you think Buster’s nightmare was about?” The child said, “The nightmare was about being afraid of getting hurt again by someone mean.”